The purpose of the NHANES (National Health and Nutrition Examination Survey) Initial Epidemiologic Follow-up Survey was to conduct a longitudinal study of 14,407 adults originally surveyed in 1971-1975, to investigate subsequent health and mortality outcomes. Respondents have been traced and re-examined. Additional information was obtained from hospital records, the National Death Index and death certificates. The NHANES Initial Follow-up Survey was completed in 1984. The purpose of this intramural project is to examine the relationship of chemopreventive and nutritional factors as well as constitutional factors to cancer in this representative population. This study provides an opportunity to examine these factors and potentially confounding or modifying factors in a prospective fashion, and to examine the effectiveness of dietary agents which are currently of great interest for cancer prevention. The relationship of baseline vitamin use, biochemical or nutritional measures, and subsequent health status will be examined. In addition, descriptive data and trends in potential risk factors or protective factors over time will be examined. A continued follow-up, of the elderly (those over 75 years of age), started in 1985 while the entire cohort will be followed up in 1986.